1) Field of the Invention
The invention is directed to a surgical device for removing tissue cells from a biological structure. The device includes a fluid jet device for generating a fluid jet capable of separation and a suction device for suctioning off separated tissue cells and the injected fluid, as well as an operating handpiece connected with the fluid jet device and the suction device. The operating handpiece includes an outer suction tube and an inner injection cannula extending through the suction tube, the outer suction tube and the inner injection cannula form therebetween an annular suction channel. The suction tube includes one or more rows of radial suction openings. The distal end of the injection cannula is closed by a conical tip and the surface of the conical tip includes a nozzle slit that forms a flat jet.
Such devices are used in surgical hospitals for cosmetic purposes and for treating illnesses, as well as for harvesting tissue cells that can reproduce.
2) Description of the Related Art
It is generally known to suction off, for example, excess fatty tissue cells for cosmetic purposes. In a first step, a pressurized working fluid is injected into the fatty tissue, dissolving the fatty tissue in the working fluid by a chemical reaction. In a second step, a suction cannula having a reduced pressure is pushed into the corresponding fatty tissue, whereby the suction force tears the fatty tissue completely out of the connective tissue and removes the mixture of dissolved fatty tissue and working fluid. The mixture is then collected in a receiving container and subsequently disposed of. The suction cannula is formed so as to have several suction openings that are uniformly distributed about its periphery.
U.S. Pat. No. 5,968,008 discloses a suction device for fatty tissue of this type which includes an injection line arranged inside the suction cannula. The injection line terminates in an outlet opening, from which a circular liquid jet exits. With his device, the two separate steps of injecting working fluid and suctioning off fatty tissue using the working fluid are now performed simultaneously, so that the surgical procedure can be performed in less time and continuously. DE 200 09 786 U1 describes a similar suction device for fatty tissue with an injection line having a slit-like exit opening, from which the jet of the working fluid exits in a fan-like shape. This fan-shaped fluid jet supposedly improves the distribution of the working fluid, so that a larger volume of fatty tissue can be uniformly removed.
All the aforedescribed suction devices for fatty tissue are designed to tear the fatty tissue out of the connected tissue through the combined effect of the dissolving power of the working fluid and the force of the suction flow. However, the combined effect from these two components causes problems, because the suction force has a constant value, whereas the dissolution process by the working fluid is time-dependent. Because suction force and dissolving power are not coordinated with each other, the constant suction force is too small at the beginning of the time-dependent dissolution process, as not enough tissue cells have been dissolved, and is too large at the end of the dissolution process, because the tissue cells have all been exposed at the end of the dissolution process. Consequently, the time during which the tissue cells are exposed to the working fluid is either too long or the tissue cells are exposed to an excessively large suction force. In both situations, the tissue cells to be suctioned off as well as tissue cells that should be preserved are destroyed. The human body is subjected to stress which complicates and prolongs the healing process.
The suctioned-off fatty tissue cells are destroyed by the suction process and by the detrimental influence of the working fluid and can then no longer be used.
DE 100 33 278 A1 of the Applicant describes for the first time a device for removing tissue cells from a biological structure. The device is primarily intended to completely separate the excess fatty tissue cells from the adjacent tissue cells by a pressurized fluid jet. The exit opening of the injection line is shaped to form a flat jet is with a frontal cutting edge that operates like a scraping device and therefore effectively peels the fatty tissue cells off. The fluid is pressurized and chemically neutral; the pressurized fluid enters in an intelligent manner between neighboring smooth and soft fatty tissue cells, urges the tissue cells apart, and thereby mechanically separates the strong tendons that hold the tissue together without destroying the tissue cells. The carefully separated tissue cells together with the neutral fluid are suctioned off by a relatively small suction force and are discharged, or alternatively, are separated again from the neutral fluid and reused. This type of surgical devices advantageously separates the fatty tissue cells solely by applying the force of the separation jet, whereas the fatty tissue cells are suctioned off together with the neutral fluid by the force of the suction flow. Unlike with prior art devices, the separation force and the suction force need not be matched and can be selected independent of each other, with the respective forces adjusted to provide the least harmful treatment for the patient. Unlike prior art devices, which produce a fluid intermixed with blood, the novel surgical tissue removal device produces a milky, white suction flow dominated by fatty tissue cells.
However, even this surgical removal device still causes stress in the human body and damage to a large percentage of fatty tissue cells.
It is the therefore an object of the invention to minimize the required separation force and the required suction force of a surgical device of this type.